1. Field of the Invention
The present invention relates to a tape guide device having an inclined post and a guide roll rising upright on its base for guiding and directing a length of recording tape from a videocassette to the rotary drum on the deck of a video recorder, so that the length of recording tape may traverse the rotary drum.
2. Related Art
As is well known, the rotary drum is inclined at a predetermined angle relative to the deck of a video recorder. The length of tape is applied to the rotary drum over approximately 180 degrees. When the rotary drum rotates at a high constant speed, the length of tape runs at a predetermined speed to send and receive signals from the magnetic heads, which are mounted on the circumference of the drum for recording and reproducing signals.
Referring to FIG. 6, the length of tape 2 is applied to the rotary drum 1 on the deck of a video recorder. For applying the length of tape 2 fed from a videocassette 3 to the rotary drum 1 a first stationary post 4, first tension posts 5, a first guide roll 6 and a first inclined post 7 are arranged on the order named on the tape-feeding side A. Likewise, a second inclined post 7, a second guide roll 6, a pinch roll-and-capstan 8 and 9, and a second stationary post 4 are arranged on the order named on the tape-winding side B.
Referring to FIG. 7, each tape guide roll 6 is rotatably mounted to a die casting base 10. Specifically the base 10 has an axle hole made therein, and the axle of the guide roll 6 is inserted in the axle hole. The axle is fastened by a screw, which is tightened by applying such a controlled torque that the slipping-off of the axle from the axle hole may be prevented, still permitting adjustment of the guide roll in respect of height.
The axle, however, is apt to loosen or shake in the axle hole, owing to the clearance between the axle and the inner circumference of the axle hole. With a view to prevent the axle from growing loosely or shaking in the axle hole an extra lock screw is used. Even though the base is made of a synthetic resin material of high-strength in place of die-casting, the base needs use of the lock screw.
In the hope of reducing such loosing problem the axle hole of the base is somewhat smaller in diameter than the axle of the guide roll, and the axle is press-fitted in the axle hole of the base. This remedy, however, requires the strict precision of making axles and axle holes, and it is almost impossible to insert the axle into the full length of the axle hole. As a matter of fact, insertion of the axle into the axle hole is limited to a very short distance.
The axle hole is so made that a very short length of the hole is somewhat smaller in diameter than the axle of the guide roll, and that the remaining length of the hole is somewhat larger in diameter than the axle, leaving a small annular clearance between the axle and the inner circumference of the hole. The axle is press-fitted in the axle hole of the base, and then, the axle is tilted more or less about the very short length of the hole where the axle is tightly gripped. As a result the length of tape is caught by one of the flanges 11a and 11b between which the guide roll 6 is rotatably sandwiched. Then, the length of tape is damaged or is prevented from running at a controlled speed.
In view of the above one object of the present invention is to provide a tape guide device whose guide roll is guaranteed to be free of shaking, assuring the stable tape running, and facilitating precise height-adjustment of the guide roll without requiring any strict boring of the base relative to the axle size.
To attain this object a tape guide device having an inclined post and a guide roll rising upright on its base for guiding and directing a length of recording tape fed from a videocassette to the rotary drum on the deck of a video recorder, is improved according to the present invention in that the base is made of a synthetic resin material, and has an axle hole made therein for press-fitting the axle of the guide roll, the upper end of the axle hole being tapped, and the axle hole having at least one rib projecting inward from its circumference, thus making the axle threadedly engaged with the upper end of the axle hole to be press-fitted in the axle hole with the rib or ribs pressed and slightly deformed.
Two ribs may be formed apart from each other on the inner circumference of the axle hole on the side opposite to the inclined post. Otherwise, two ribs may be formed apart from each other on the inner circumference of the axle hole on the same side as the inclined post.
The tape guide device is basically similar to the conventional one in structure; the axle of the guide roll is press-fitted in the axle hole of the resin base.
The feature of the tape guide device resides in two ribs being formed on the inner circumference of the axle hole. The axle is press-fitted in the axle hole while deforming the ribs projecting from the inner surface of the axle hole, thereby assuring that the axle is inserted into the substantial depth of the axle hole in the tight gripping condition. Thanks to the deformable ribs the boring allowance relative to the axle size is less strict than that which is required in boring the base of the conventional tape guide device.
Other objects and advantages of the present invention will be understood from the following description of a tape guide device according to one preferred embodiment of the present invention, which is shown in accompanying drawings.